TW202019823A - Ionic conductor containing high-temperature phase of LiCB9H10, method for manufacturing same, and solid electrolyte for all-solid-state battery containing said ion conductor - Google Patents

Abstract

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Description

Ion conductor containing high temperature phase of LiCB9H10 and its manufacturing method, and solid electrolyte for all solid battery containing the ion conductor

The present invention relates to an ion conductor containing a high-temperature phase of LiCB ₉ H ₁₀ and a method for manufacturing the same, and a solid electrolyte for an all-solid battery containing the ion conductor.

In recent years, the demand for lithium ion secondary batteries has increased in applications such as mobile information terminals, mobile electronic equipment, electric vehicles, hybrid vehicles, and stationary power storage systems. However, current lithium-ion secondary batteries use flammable organic solvents as electrolytes, and require a robust exterior to avoid leakage of organic solvents. In addition, in portable computers, there is a need to adopt a structure to prevent the risk of electrolyte leakage, etc., and restrictions on the structure of the equipment have also appeared.

Further, its use is widely used in moving bodies such as automobiles or airplanes, and there is a demand for a large capacity of stationary lithium ion secondary batteries. Under such circumstances, there is a tendency to pay more attention to safety than before, and is committed to the development of all-solid lithium ion secondary batteries that do not use harmful substances such as organic solvents. For example, with regard to solid electrolytes in all-solid lithium-ion secondary batteries, it has been studied to use oxides, phosphoric acid compounds, organic polymers, sulfides, complex hydrides, and the like.

All solid-state batteries are roughly classified into a thin film type and a bulk type. The thin-film type uses vapor deposition to form an ideal interface junction, but the electrode layer is as thin as a few μm, the electrode area is also small, the energy that can be stored per unit is small, and the cost becomes high. Therefore, it is not suitable as a large power storage device that needs to store much energy or a battery for an electric vehicle. On the other hand, the thickness of the stacked electrode layer can be made into tens of μm to 100 μm, and an all-solid battery with high energy density can be made.

Among solid electrolytes, the sulfide or complex hydride system has high ion conductivity and is relatively soft, so that it is easy to form a solid-solid interface. Some people are considering its application to a stacked all-solid battery (Patent Literature) 1 and 2).

However, the conventional sulfide solid electrolyte has the property of reacting with water, and there is a problem that the sulfide generates hydrogen sulfide and the ion conductivity decreases after reacting with water. On the other hand, the complex hydride solid electrolyte tends to have a slightly lower ion conductivity than the sulfide solid electrolyte, and it is desired to improve the ion conductivity.

Patent Document 3 describes a solid electrolyte called carborane, but does not describe ion conductivity. [Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent 6246816 [Patent Literature 2] WO2017-126416 [Patent Literature 3] US2016/0372786A1

[Problems to be solved by the invention]

An object of the present invention is to provide an ion conductor excellent in various characteristics such as ion conductivity, a method for manufacturing the same, and a solid electrolyte for an all-solid battery containing the ion conductor. [Means to solve the problem]

In order to solve the above-mentioned problems, the inventors of the present invention have found that an ion conductor obtained by mixing LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ at a specific molar ratio can solve the above-mentioned problems. That is, the present invention is as follows. >1>A method for manufacturing an ion conductor, which is a method for manufacturing an ion conductor containing LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ and includes the following steps: LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ are replaced by LiCB ₉ H ₁₀ /LiCB ₁₁ H ₁₂ =Molar ratio of 1.1 to 20 is mixed. >2> The manufacturing method of the ion conductor according to >1>, wherein the mixing is performed by performing mechanical polishing treatment. >3> The manufacturing method of the ion conductor according to >2>, wherein the implementation time of the mechanical polishing treatment is 1 to 48 hours. >4>The method for manufacturing an ion conductor according to any one of >1>to>3>, wherein the ion conductor obtained in X-ray diffraction measurement at 25°C is at least 2θ=14.9±0.3deg , 16.4±0.3deg, 17.1±0.5deg with X-ray diffraction peak, and according to A=(16.4±0.3deg X-ray diffraction intensity)-(20deg X-ray diffraction intensity), B=(17.1± The calculated intensity ratio (B/A) of 0.5 deg X-ray diffraction intensity)-(20 deg X-ray diffraction intensity) is 1.0-20. >5> An ion conductor containing lithium (Li), carbon (C), boron (B) and hydrogen (H), and in X-ray diffraction measurement at 25°C, at least 2θ=14.9±0.3deg, 16.4±0.3deg, 17.1±0.5deg with X-ray diffraction peak, and according to A=(16.4±0.3deg X-ray diffraction intensity)-(20deg X-ray diffraction intensity), B=(17.1±0.5 The intensity ratio (B/A) calculated by X-ray diffraction intensity of deg)-(X-ray diffraction intensity of 20 deg) is 1.0-20. >6> The ion conductor of >5>, wherein the ion conductor contains LiCB ₉ H ₁₀ . >7> The ion conductor of >6>, wherein the ion conductor further contains LiCB ₁₁ H ₁₂ . >8>The ion conductor according to any one of >5>～>7>, wherein, in the measurement of Raman spectroscopy, they are respectively at 749cm ^-1 (±5cm ^-1 ) and 763cm ^-1 (±5cm ^-1 ) Has a peak. >9> The ion conductor according to any one of >5>to>8>, wherein the ion conductivity at 25°C is 1.0 to 10 mScm ^-1 . >10> A solid electrolyte for an all-solid battery, containing the ion conductor as described in any one of >5> to >9>. >11>An electrode made of solid electrolyte connected to lithium metal in an all-solid battery like >10>. >12> An all-solid battery with electrodes like >11>. [Effect of invention]

According to the present invention, it is possible to provide an ion conductor excellent in various characteristics such as ion conductivity, a method for manufacturing the same, and a solid electrolyte for an all-solid battery containing the ion conductor.

Hereinafter, embodiments of the present invention will be described. In addition, the present invention is not limited by the materials, configurations, etc. described below, and various changes can be made within the scope of the gist of the present invention.

1. Ion conductor According to one embodiment of the present invention, an ion conductor is provided, which contains lithium (Li), carbon (C), boron (B), and hydrogen (H). The above embodiment preferably contains a high-temperature phase (high ion-conducting phase) as crystallized LiCB ₉ H ₁₀ , and more preferably contains LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ .

Ion conductive system of the present invention in the Raman spectroscopy, preferably has a basis (± 5cm ^-1) of the respective LiCB ₉ H ₁₀ of 749cm ^-1 (± 5cm ^-1) and based LiCB 763cm ^-1 ₁₁ H ₁₂ of Peak. There may be peaks in other regions, but the peaks exhibiting different characteristics are those described above.

The ion conductor of the present invention preferably contains a high-temperature phase of LiCB ₉ H ₁₀ as crystals. LiCB ₉ H ₁₀ has a high-temperature phase and a low-temperature phase according to its crystalline state. The high-temperature phase at high temperatures (eg, about 75-150°C) has high ionic conductivity, but around room temperature (eg, about 20-65°C) It becomes a low-temperature phase, and the ion conductivity decreases. The ion conduction system of the present invention has an X-ray diffraction peak based on the high-temperature phase of LiCB ₉ H ₁₀ at least at 2θ=14.9±0.3deg, 16.4±0.3deg, 17.1±0.5deg at 25°C X-ray diffraction measurement unit. It is better to use A=(16.4±0.3deg X-ray diffraction intensity)-(20deg X-ray diffraction intensity), B=(17.1±0.5deg X-ray diffraction intensity)-(20deg X-ray diffraction intensity The calculated intensity ratio (B/A) is in the range of 1.0 to 20, more preferably in the range of 1.0 to 15, especially in the range of 1.0 to 10. When the strength ratio (B/A) is in the range of 1.0 to 20, the phase transition temperature is reduced by the solid solution of LiCB ₁₁ H ₁₂ to the high-temperature phase of LiCB ₉ H _{10, and} the high ion conductivity can be maintained even near room temperature status. The establishment of this solution is when LiCB ₉ H ₁₀ /LiCB ₁₁ H ₁₂ =Moore ratio above 1.1. It is preferably LiCB ₉ H ₁₀ /LiCB ₁₁ H ₁₂ =1.1～20, more preferably LiCB ₉ H ₁₀ /LiCB ₁₁ H ₁₂ =1.25～10, especially LiCB ₉ H ₁₀ /LiCB ₁₁ H ₁₂ =1.5～9, The ion conductivity exhibits a high value in this range. In addition, even if the ion conductor of the present invention contains an X-ray diffraction peak other than the above, the desired effect can be obtained. In addition, the ion conductor of the present invention may contain components other than lithium (Li), carbon (C), boron (B), and hydrogen (H). As for other components, for example, oxygen (O), nitrogen (N), sulfur (S), fluorine (F), chlorine (Cl), bromine (Br), iodine (I), silicon (Si), germanium (Ge), phosphorus (P), alkali metals, alkaline earth metals, etc.

The above ion conduction system is soft and can be formed into an electrode layer and a solid electrolyte layer by cold pressing. In addition, the electrode layer and the solid electrolyte layer formed in this manner have better strength than the case of a sulfide solid electrolyte or an oxide solid electrolyte with a large content. Therefore, by using the ion conductor of the present invention, it is possible to produce an electrode layer and a solid electrolyte layer that have good formability and are less likely to break (it is less likely to cause cracks). In addition, because the ion conductor of the present invention has a low density, a lighter electrode layer and solid electrolyte layer can be produced. This is preferable because it can reduce the weight of the entire battery. In addition, when the ion conductor of the present invention is used in a solid electrolyte layer, the interface resistance with the electrode layer can be reduced. In addition, the above-mentioned ion conductor will not decompose even if it is exposed to moisture or oxygen, and will not produce dangerous toxic gas.

The ion conductivity of the ion conductor of the present invention at 25°C is preferably 1.0 to 10 mScm ^-1 , more preferably 2.0 to 10 mScm ^-1 .

2. Method of manufacturing an ion conductor According to other embodiments of the present invention, there is provided a method of manufacturing the above ion conductor, which is a method of manufacturing an ion conductor including LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ , including LiCB ₉ H Step of mixing ₁₀ and LiCB ₁₁ H ₁₂ at a molar ratio of LiCB ₉ H ₁₀ /LiCB ₁₁ H ₁₂ =1.1-20.

For LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ which are raw materials, commercially available ones can be used. In addition, its purity should be above 95%, more preferably above 98%. By using a compound whose purity is within the above range, it is easy to obtain desired crystals.

The mixing ratio of LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ needs to be a molar ratio of LiCB ₉ H ₁₀ /LiCB ₁₁ H ₁₂ =1.1 or more. It is preferably LiCB ₉ H ₁₀ /LiCB ₁₁ H ₁₂ =1.1～20, more preferably LiCB ₉ H ₁₀ /LiCB ₁₁ H ₁₂ =1.25～10, especially LiCB ₉ H ₁₀ /LiCB ₁₁ H ₁₂ =1.5～9. As mentioned above, in this range, the ion conductivity exhibits a particularly high value.

The mixing of LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ should be carried out in a passive gas environment. Examples of the passive gas include helium, nitrogen, and argon, and argon is preferred. The concentration of moisture and oxygen in the passive gas should be controlled to be low, more preferably the concentration of moisture and oxygen in the passive gas is less than 1 ppm.

The method of mixing is not particularly limited, and can be used for stirring and mixing in a solvent. Mechanical mixing can also be used, and for example, a method using a crusher, a ball mill, a planetary ball mill, a bead mill, a spin-revolving mixer, a high-speed stirring type mixing device, a drum mixer, and the like. Among these, planetary ball mills with excellent crushing power and mixing power are more preferable, and mechanical grinding treatment and mixing are preferably performed by using planetary ball mills. The mechanical mixing should be carried out by dry method, or it can be carried out under solvent. Regardless of the above method, there is no particular limitation in terms of the solvent, and examples include nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran or diethyl ether, N,N-dimethylformamide, N,N- Alcohol-based solvents such as dimethylacetamide, methanol or ethanol.

The mixing time differs depending on the mixing method, and in the case of stirring and mixing in the solvent, it is, for example, 1 to 48 hours, preferably 5 to 24 hours. In addition, when a solvent is used, the mixing time can be shortened. The mixing time in mechanical mixing is, for example, 1 to 24 hours, preferably 5 to 20 hours when a planetary ball mill is used.

The reaction pressure is usually in the range of 0.1 Pa to 2 MPa as the absolute pressure. It should be 101kPa～1MPa.

By the above-described ion-producing method of the present invention obtained by the conductor, in the Raman spectrum measurement, it should be based on the LiCB ₉ H ₁₀ 749cm ^-1 (± 5cm ^-1) and based LiCB 763cm ^-1 ₁₁ H ₁₂ in the ( ±5cm ^-1 ) Each has a peak. In addition, in the X-ray diffraction measurement at 25°C, at least 2θ=14.9±0.3deg, 16.4±0.3deg, 17.1±0.5deg has an X-ray diffraction peak based on the high temperature phase of LiCB ₉ H ₁₀ , and From A=(16.4±0.3deg X-ray diffraction intensity)-(20deg X-ray diffraction intensity), B=(17.1±0.5deg X-ray diffraction intensity)-(20deg X-ray diffraction intensity) The calculated intensity ratio (B/A) is preferably in the range of 1-20, more preferably in the range of 1.0-15, and particularly preferably in the range of 1.0-10.

3. All solid battery The ion conductor of the present invention can be used as a solid electrolyte for an all-solid battery. Therefore, according to one embodiment of the present invention, there is provided a solid electrolyte for an all-solid battery including the ion conductor. In addition, according to a further embodiment of the present invention, there is provided an all-solid battery using the solid electrolyte for the all-solid battery.

In this specification, an all-solid battery refers to an all-solid battery in which lithium ions are responsible for electrical conduction, especially an all-solid lithium-ion secondary battery. An all-solid battery has a structure in which a solid electrolyte layer is arranged between a positive electrode layer and a negative electrode layer. One or more layers of any one of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer may contain the ion conductor of the present invention as a solid electrolyte. When it is used for the electrode layer, it is more suitable for the positive electrode layer than the negative electrode layer. This is because the positive electrode layer is less likely to cause side reactions. When the ion conductor of the present invention is contained in the positive electrode layer or the negative electrode layer, the ion conductor is used in combination with a known positive electrode active material or negative electrode active material for lithium ion secondary batteries. As for the positive electrode layer, if a stacked type obtained by mixing an active material and a solid electrolyte is used, the capacity per unit becomes larger, which is preferable.

The all-solid battery is produced by forming and laminating the above-mentioned layers, and the forming method and the lamination method of each layer are not particularly limited. For example, if a solid electrolyte and/or electrode active material is dispersed in a solvent and is made into a slurry, it is coated by a doctor blade, spin coater, etc., and rolled to form a film; using vacuum evaporation method, ion plating The gas-phase method of film formation and lamination by sputtering, sputtering, laser ablation, etc.; powder is formed by hot pressing or cold pressing without applying temperature, and it is subjected to lamination pressing method. Since the ion conductor of the present invention is relatively soft, it is particularly suitable for forming a battery by pressing and forming and laminating. In addition, it is also possible to form an electrode layer pre-added with an active material, a conductive aid, a binder, etc., a solution obtained by dissolving a solid electrolyte in a solvent, or a slurry obtained by dispersing a solid electrolyte in a solvent and flowing into it, after which By removing the solvent, the solid electrolyte enters the electrode layer.

As far as the environment for making an all-solid battery is concerned, it should be implemented in a passive gas or dry room where the moisture is controlled. As far as moisture control is concerned, the dew point is preferably in the range of -10°C to -100°C, more preferably the dew point is in the range of -20°C to -80°C, especially the range of dew point is -30°C to -75°C. This is because, although the hydrolysis rate of the ion conductor of the present invention is extremely slow, it is still necessary to prevent the ionic conductivity from being reduced due to the formation of hydrates. [Example]

Hereinafter, the present invention will be described in detail by examples, but the content of the present invention is not limited by this.

>Preparation of ion conductor> (Example 1) LiCB ₉ H ₁₀ (manufactured by Katchem) and LiCB ₁₁ H ₁₂ (manufactured by Katchem) in a glove box under an argon atmosphere to become LiCB ₉ H ₁₀ : LiCB ₁₁ H ₁₂ =9: Measure 100 mg in a molar ratio and pre-mix it with an agate mortar. Then, the pre-mixed raw materials were added to a 45 mL SUJ-2 tank, and SUJ-2 balls (φ7mm, 20 pieces) were added to completely seal the tank. This tank was installed in a planetary ball mill (P7 manufactured by Fritsch), and mechanical polishing was performed at a rotation speed of 400 rpm for 20 hours to obtain an ion conductor. As a result of X-ray diffraction, the ion conductor obtained contains the high-temperature phase of LiCB ₉ H ₁₀ .

(Example 2) The mixed molar ratio of LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ was changed to LiCB ₉ H ₁₀ : LiCB ₁₁ H ₁₂ = 8:2, except that ions were produced in the same manner as in Example 1. Conductor.

(Example 3) An ion was produced in the same manner as in Example 1 except that the mixing molar ratio of LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ was changed to LiCB ₉ H ₁₀ : LiCB ₁₁ H ₁₂ = 7:3. Conductor.

(Example 4) In the same manner as in Example 1, except that the mixing molar ratio of LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ was changed to LiCB ₉ H ₁₀ : LiCB ₁₁ H ₁₂ = 6:4. Conductor.

(Comparative Example 1) An ion was produced in the same manner as in Example 1 except that the mixing molar ratio of LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ was changed to LiCB ₉ H ₁₀ : LiCB ₁₁ H ₁₂ =5:5. Conductor. According to the result of X-ray diffraction, the obtained ion-conducting system LiCB ₉ H ₁₀ and LiCB ₁₁ H _{12 are} mixed.

>X-ray diffraction measurement> For the ion conductor powders obtained in Examples 1 to 4 and Comparative Example 1, a Lindemann glass capillary (outer diameter 0.5) was used under an argon atmosphere at room temperature (25°C) mm, thickness 0.01 mm), X-ray diffraction measurement (X'pert Pro manufactured by PANalytical, CuKα: λ=1.5405 Angstroms) was carried out. The obtained X-ray diffraction peaks are shown in FIGS. 1A and 1B. For comparison, FIG. 1A also shows the X-ray diffraction peaks of LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ as raw materials. In Examples 1 to 4, X-ray diffraction peaks were observed at least at 2θ=14.9±0.3 deg, 16.4±0.3 deg, and 17.1±0.5 deg. In addition, when the intensities of the peak positions of 16.44 deg and 17.07 deg of the high-temperature phase of LiCB ₉ H _{10 are} set to A and B, the intensity ratio (B/A) is summarized in Table 1. In addition, the respective intensities set the value of 2θ=20deg as the reference line, by A=(16.44deg X-ray diffraction intensity)-(20deg X-ray diffraction intensity), B=(17.07deg X Ray diffraction intensity)-(X-ray diffraction intensity of 20deg) is calculated. Examples 1 to 4 are known to be solid solutions because they coincide with the peak position of the high-temperature phase of LiCB ₉ H ₁₀ , and it is known that Comparative Example 1 is a low-temperature phase of LiCB ₉ H ₁₀ and a mixed phase with LiCB ₁₁ H ₁₂ Outside the solid solution area.

[Table 1] Table 1 Intensity ratio of Examples and Comparative Examples

>Raman Spectroscopy> (1) Sample preparation The measurement sample is prepared using a sealed container with quartz glass (Φ60mm, thickness 1mm) as the optical window on the upper part. In a glove box under an argon atmosphere, after storing the liquid in a state where the sample is in contact with quartz glass, the container is sealed and taken out of the glove box, and Raman spectroscopy is performed. (2) Measurement conditions A laser Raman spectrophotometer NRS-5100 (manufactured by Nippon Spectroscopy Co., Ltd.) was used for measurement at an excitation wavelength of 532.15 nm and an exposure time of 5 seconds. The obtained Raman spectrum is shown in Figure 2. LiCB ₉ H ₁₀ has a peak at 749 cm ^-1 , and LiCB ₁₁ H ₁₂ has a peak at 763 cm ^-1 . In addition, the Raman shift value comes from the bonding and is hardly affected by the crystalline state. A peak at 763cm ^-1-based portion 2 of Example 1 to the shoulder of the embodiment 749cm ^-1, 749cm ^-1 peak portion of the line of Examples 3-4 and Comparative Example 1 shoulder 763cm ^-1, the apparent Jie The existence of LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ .

>Measurement of ion conductivity> In the glove box under argon atmosphere, the ion conductors obtained in Examples 1 to 4 and Comparative Example 1, LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ as raw materials were supplied to uniaxial molding (240MPa), making a disc with a thickness of about 1mm and φ8mm. In the temperature range from room temperature to 150°C or room temperature to 80°C, the temperature is raised and lowered at 10°C intervals, and the AC impedance measurement is performed by using the two-terminal method of the lithium electrode (HIOKI 3532-80, chemical impedance meter ) To calculate the ion conductivity. The measurement frequency range is 4 Hz to 1 MHz, and the amplitude is 100 mV.

The measurement results of the respective ion conductivity are shown in Fig. 3. In addition, the ion conductivity at room temperature (25°C) is shown in Table 2. In addition, in Examples 1 to 4 and Comparative Example 1, the phenomenon that the ion conductivity at the low temperature drops sharply in LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ of the raw materials was not observed. However, it can be seen that the difference in ion conductivity between Comparative Example 1 and Examples 1 to 4 is large. Even in Example 4 having the lowest ion conductivity among Examples 1 to 4, the ion conductivity at room temperature is the same as that of Comparative Example 1. More than 2 times.

【Table 2】 Table 2 Ionic conductivity at 25℃

(Example 5)> Dissolution and precipitation test for lithium symmetry unit> The powder of the ion conductor obtained in Example 3 was added to a powder tablet forming machine with a diameter of 8 mm, and pressed into a disk shape by pressing at a pressure of 143 MPa. Disk-shaped pellets laminated with a solid electrolyte layer (300 μm) were obtained. A lithium metal foil (manufactured by Honjo Metal Co., Ltd.) with a thickness of 200 μm and a diameter of 8 mm was attached to both sides of the pellets, and a SUS304-made all-solid battery restraint test unit (manufactured by Treasure Springs) was placed and sealed to produce an evaluation unit. The above operations are performed in a glove box under an argon atmosphere. For the obtained evaluation unit, a potentiostat/galvanostat (VMP3 manufactured by Bio-Logic) was used, and the current was circulated by inverting the polarity every 0.5 hour by measuring the temperature at 25°C and the current density at 0.2 mA/cm ^-2 . For 1 cycle (1 hour as 1 cycle), the voltage applied between the electrodes of the evaluation unit was measured. The results are shown in Figure 4. The overvoltage is as small as 0.01V and stable, and does not exhibit abnormal voltage. Even after 100 cycles, there was only a slight increase in overvoltage, which showed that good Li repeatedly dissolved and precipitated.

(Example 6) >Charge and discharge test> (Preparation of positive active material) Sulfur (S) (manufactured by Sigma-Aldrich Co. LLC, purity 99.98%), Ketjen black (manufactured by Lion Specialty Chemicals Co., Ltd., EC600JD), and Maxsorb (registered trademark) (manufactured by Kansai Thermochemical) , MSC30), in a way to become S: Ketchen Black: Maxsorb (registered trademark) = 50: 25: 25 weight ratio is added to the 45mL SUJ-2 cans. Add SUJ-2 ball (φ7mm, 20 pieces) to seal the can completely. This tank was installed in a planetary ball mill (P7 manufactured by Fritsch), and mechanical grinding was performed at 400 rpm for 20 hours to obtain an S-carbon composite positive electrode active material. (Preparation of positive electrode layer powder) In order to become the S-carbon composite positive electrode active material prepared above: the ion conductor obtained in Example 3 = 1:1 (weight ratio), the powder was measured in a glove box and mixed by a mortar to prepare Formed into the positive electrode layer powder.

(Production of all solid battery) The powder of the ion conductor obtained in Example 3 was added to a powder tablet forming machine with a diameter of 10 mm, and pressed into a disc shape (formation of a solid electrolyte layer) by pressing at a pressure of 143 MPa. Without taking out the molded product, the positive electrode layer powder prepared as described above was added to a tablet molding machine, and molded into a whole by a pressure of 285 MPa. In this way, disk-shaped pellets obtained by laminating a positive electrode layer (75 μm) and a solid electrolyte layer (300 μm) were obtained. On the opposite side of the positive electrode layer of the pellets, a metal lithium foil (manufactured by Honjo Metal Co., Ltd.) with a thickness of 200 μm and φ8 mm was attached as a lithium negative electrode layer, and a SUS304-made all-solid battery restraint test unit (manufactured by Baoquan) was placed. And sealed to make an all-solid secondary battery.

(Charge and discharge test) For the all-solid secondary battery fabricated as described above, a potentiostat/galvanostat (VMP3 manufactured by Bio-Logic) was used to measure the temperature at 25°C, cut-off voltage 1.0-2.5V, and 0.1C charge. For a constant current with a discharge rate, a charge-discharge test is performed from the beginning of discharge. In addition, the discharge capacity is expressed as the value per 1 g of the sulfur-based electrode active material obtained from the battery tested. In addition, it is calculated by Coulomb efficiency=charge capacity/discharge capacity. The results are shown in Figure 5. Although a large irreversible capacity was observed during the first discharge, after the second cycle, it exhibited a high Coulomb efficiency of over 98%. As far as the cycle characteristics are concerned, relative to the initial discharge capacity of 1900mAh/g, the second cycle system has a large drop of 1300mAh/g, stable after the third cycle, and the discharge capacity of the 20th cycle is 1100mAh/g. Large capacity can be obtained.

no

[FIG. 1A] FIG. 1A shows X-ray diffraction peaks of the powders of ion conductors obtained in Examples 1 to 4 and Comparative Example 1. [Fig. 1B] Fig. 1B is a magnification of the X-ray diffraction spectrum of a part of Fig. 1A. [FIG. 2A] FIG. 2 shows the Raman spectra of the ion conductors obtained in Examples 1 to 4 and Comparative Example 1. [Fig. 2B] Fig. 2B enlarges a part of the Raman spectrum of Fig. 1A. [FIG. 3] FIG. 3 shows the measurement results of the ion conductivity of the ion conductors obtained in Examples 1 to 4 and Comparative Example 1. [FIG. 4A] FIG. 4A shows the results of measuring the voltage between the electrodes of the evaluation unit in Example 5. FIG. [FIG. 4B] FIG. 4B is an enlarged part of FIG. 4A. [Fig. 5A] Fig. 5A shows the results of the charge and discharge test in Example 6. [FIG. 5B] FIG. 5B shows the results of the charge and discharge test in Example 6.

Claims (12)

A method for manufacturing an ion conductor is a method for manufacturing an ion conductor containing LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ and includes the following steps: LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ are replaced by LiCB ₉ H ₁₀ /LiCB ₁₁ H ₁₂ = 1.1 to 20 molar ratios are mixed. The method for manufacturing an ion conductor as claimed in item 1 of the patent scope, wherein the mixing is performed by performing mechanical polishing treatment. For example, the method for manufacturing an ion conductor according to item 2 of the patent application scope, wherein the implementation time of the mechanical polishing treatment is 1 to 48 hours. The method of manufacturing an ion conductor according to any one of the items 1 to 3 of the patent application scope, wherein, in X-ray diffraction measurement at 25°C, the obtained ion conductor is at least 2θ=14.9±0.3deg, 16.4 ±0.3deg, 17.1±0.5deg with X-ray diffraction peak, and according to A=(16.4±0.3deg X-ray diffraction intensity)-(20deg X-ray diffraction intensity), B=(17.1±0.5deg The calculated X-ray diffraction intensity)-(20 deg X-ray diffraction intensity) calculated intensity ratio (B/A) is 1.0-20. An ion conductor containing lithium (Li), carbon (C), boron (B), and hydrogen (H), and in X-ray diffraction measurement at 25°C, at least 2θ=14.9±0.3deg, 16.4±0.3 deg, 17.1±0.5deg have X-ray diffraction peak, and according to A=(16.4±0.3deg X-ray diffraction intensity)-(20deg X-ray diffraction intensity), B=(17.1±0.5deg X The intensity ratio (B/A) calculated by (ray diffraction intensity)-(20 deg X-ray diffraction intensity) is 1.0 to 20. An ion conductor as claimed in item 5 of the patent scope, wherein the ion conductor contains LiCB ₉ H ₁₀ . An ion conductor as claimed in item 6 of the patent scope, wherein the ion conductor further contains LiCB ₁₁ H ₁₂ . An ion conductor according to any one of items 5 to 7 of the patent application range, wherein, in the measurement of Raman spectroscopy, there are peaks at 749cm ^-1 (±5cm ^-1 ) and 763cm ^-1 (±5cm ^-1 ), respectively unit. An ion conductor according to any one of items 5 to 8 of the patent application range, wherein the ion conductivity at 25°C is 1.0 to 10 mScm ^-1 . A solid electrolyte for an all-solid battery, containing the ion conductor as described in any one of patent application items 5 to 9. An electrode is formed by connecting a solid electrolyte used in an all-solid battery of the patent application item 10 and metallic lithium. An all-solid battery with electrodes as claimed in item 11 of the patent scope.

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